1. Field of the Invention
The present invention relates to a handling device, in particular to a device for handling the test heads of a wafer tester, including a mount for the test head disposed rotatably about its longitudinal axis on a supporting part, a frame column on which the supporting part is vertically adjustable relative to the frame column via at least one linear bearing and a weight balancing device for balancing the weight of the test head and the mount.
2. Description of the Related Art
A test head handling device of the above type is disclosed in applicant's German patent publication DE 195 17 330. That handling device comprises a mount for the test head which is vertically and horizontally adjustable relative to at least one vertical member. The mount is adjustably guided horizontally on a supporting part. The supporting part in turn is vertically guided adjustably on the at least one vertical member. Furthermore that handling device is provided with a weight balancing device for balancing the weight of the test head of the mount and of the supporting part. The weight balancing device includes balance weights and ribbed belts and guide pulleys connecting the weights to the supporting part.
High dimensional accuracy and good accessibility for adjusting the test head are required when the handling device is employed in known wafer testers. Since such wafer testers are put to use in a clean room environment they should have a minimum space requirement. Furthermore, good accessibility to the wafer tester is desirable, especially when to system is to be serviced.